Method and apparatus for hot rolling strip



Jan. 29, 1935. J. A. SMITMANS 7 1,989,532

METHOD AND APPARATUS FOR HOT ROLLING STRIP I Filed Aug. 29. 1933 WITNESSES gs INVENTOR wasmm QQQ y g i Arron Hzvo Patented Jan. 29, 1935 METHOD AND APPARATUS FOR n01 ROLLING s'rm John A. Smitmans, Pittsburgh, Pa., assignor to United Engineering & Foundry Company, Pittsburgh, Pa-, a corporation of Pennsylvania Application August 29,

15 Claims.

My invention relates to rolling-mill layouts and particularly to hot strip mills for preparing slabs and rolling them into sheet-metal strip.

In the operation of hot rolling metal strip from 5 slabs it is necessary, before beginning reduction rolling, to remove any scale from the slabs that may have formed thereon during their heating or prior thereto. Heretofore, because of the time required to prepare each slab and place it in position for reduction rolling, it has been difiicult to avoid the production of additional scale on the highly heated slabs.

In the preparation of the slabs for reduction rolling, it has been necessary heretofore to employ expensive and complicated mechanism for turning the slabs through an angle of 90 and for pushing them to a roll stand in order that they might be cross rolled for the purpose of increasing their width to that desired for the finished sheet-metal strip. Turntables have been employed for turning the slabs and, in addition to the time required to operate them, it has been necessary to provide skilled operators for the turntables in order to insure that the partially rotated slab would enter the roll stand in proper position.

It will be appreciated that all of these operations require considerable time and that during this period additional scale may form on the very hot metal. Also, if the slab does not enter the roll-stands of the strip mill proper entirely free from scale the latter persists throughout the entire rolling operation and is present in the finished product.

In order to avoid the employment of turntables which are complicated and require skilled operators and which necessitate the use of complicated.

and expensive pusher mechanisms, I'provide a rolling mill system in which the use of turntables is entirely eliminated. The directions of movement of the slabs are changed but it is not necessary to rotate the slabs because the apparatus is arranged to receive them with a change in their direction of movement rather than a change in their angular position.

In case the slabs require cross-rolling to increase their width they are passed through a broadside mill whichmay be arranged in series with a scale breaker, the order in which they occur not being fixed but preferably the scale breaker is first in the series. The broadside mill may accordingly receive the slabs from the scale breaker or directly from the furnace depending upon the order in which they. are arranged.

The time required for the operation of the ap- 1933, Serial No.- 687,249 (01. 29-17) 4 paratus of our invention is substantially only half that required for apparatus comprising turntables and the result is not only to avoid the expense of installing and using such apparatus but to save a great amount of time ordinarily required. Furthermore, the reduction in time of preparation of the slab for reduction rolling lengthwise thereof correspondingly reduces the tendency for additional scale to form thereon during such preparation. Y

My invention will be described in connection with the accompanying drawing in which Fig. 1 is a somewhat diagrammatic plan view of apparatus constructed and arranged in accordance with a preferred embodiment of my invention.

Referring to the drawing, slabs of any suitable size and dimensions for the production of sheetmetal strip are supplied to a plurality of furnaces l'by means of pushers 2, the operation of pushing a slab into one end of a furnace serving to 20 push a highly heated slab from the opposite end of the furnace and down an incline, not shown, to a conveyor table 3 in accordance with the usual practice. The slabs which are at a white heat have a certain amount of scale on their outer surfaces and this must be removed in order to prepare them for rolling.

On the opposite side of the conveyor table 3 from the furnace I provide steps or abutments 4 against which the slabs strike with considerable 30 force when they are ejected from the furnace and slide down the incline. This operation tends to loosen the scale on the slabs and facilitates its re- -moval.

The slabis next conveyed endwise by the conveyor 3 and passed through a scale breaker 5, driven by a motor 6 through reduction gearing '7 for the purpose of breaking the scale by slightly reducing the thickness of the slab. At the same time steam or water may beplayed on the slabs 40 in order to remove any scale thatmay have been loosened. After passing through the scale breaker 5, the slab is carried by a conveyor 8 and caused to strike a stationary stop 9 for the purpose of forcibly jarring the slab and thereby loosening any scale that may have remained.

The slab is next pushed sidewise by 'a simple ordinary pusher 11 to a roll stand 12 which is arranged broadside or at to the scale breaker 5. This roll stand, driven by 'a motor 13 through to reduction gearing 14, operates to cross-roll the slab in order to increase its width to that desired for the width of the finished strip. For example, if the slabs are 48 inches in width, they may be rolled in the roll stand 12 to increase the as width to '12 inches. The other dimensions of the slab before rolling may be, for example, 84 inches in length and 8 inches in thickness.

After passing through the roll stand 12 the widened slab is carried sidewise by transfer apparatus 16, driven by a motor 17 through reduction gearing 18, and conveyed forcibly onto a conveyor table 19 and against another stop 20 to again loosen or remove any scale that may have remained thereon. If desired, inclined skids may be substituted for the transfer apparatus 16. The foregoing operations, which require relatively little time and comparatively few mechanical operations, provide a slab that is substantially entirely free from scale and ready to be rolled into strip.

The prepared slab is then conveyed by the table 19 to a universal mill 22 having a driving motor 23, within which mill the slab is elongated lengthwise and its edges are trued by means of vertical rolls. The slab is given a sufiicient number of passes in the mill 22 to rough the slab, that is, reduce it to the desired thickness, whereupon it is conveyed by table 24 to the finishing roll stands 25, '26, 27, 28 and 29 each of which is driven by a motor 30 through reduction gear mechanism 31. The metal is rolled to desired gauge in the roll stands and is conveyed by a table 32 to a hot bed 33 for cooling. The strip may then be cooled and removed for storage or further processing asdesired.

Instead of the universal 22, there may be provided a plurality of roll stands for roughing the slabs, the number of roll stands corresponding to the number of passes required and the apparatus may then operate as a continuous mill.

In case the slabs are of such dimensions that it is not necessary to cross roll them in order to increase their width, the slabs, after being pushed from either of the furnaces 1 to the conveyor table 3, are moved in front of a pusher 35 which places them on a transfer device 36 driven by a motor 3'7 through reduction gearing 38. The transfer device 36, or inclined skids which may be substituted therefor, conveys the slabs forcibly. against a stationary abutment or stop 39 to loosen the scale thereon. They are then conveyed endwise to a scale breaker 40 that is in endwise alignment with the scale breaker 5 and is driven by the motor 6. The slabs are then conveyed to the universal mill 22, or to a roughing" mill,

as the case may be, and the operation is otherwise as described above.

Thehotslabsmaybepassedthrough thescale' breaker and broadside in series or in case the slabs are of sufiicient width the slabs pass directly from the scale breaker to the roughing mill. If the broadside mill were placed in align- ;ment with the pusher .35 similar results could be obtained because the broadside mill could permit slabs of sufficient width to pass through it without rolling for transfer to the scale breaker 40.

diminished but the arrangement and the nature of the apparatus employed in this improved layout has provided several points at which scale is loosened or removed from the slab during the preparing operation. This layout also permits the use of an inexpensive rugged pusher for en-' tering the slabs into the broadside mill. Heretofore it has been necessary to provide a very complicated mechanism for this purpose because of the presence of a turntable at this point in the travel of the slabs.

The foregoing and other advantages will be apparent to those skilled in the art of constructing and operating hot strip mills.

.I claim:

1. A hot strip mill comprising a scale breaker for receiving and treating slabs, a broadside mil. having a pass-line at 90 to that of said scale breaker for receiving slabs sidewise for cross rolling therein, and a finishing mill having a passline at right angles to said broadside mill disposed to receive the slabs as they are discharged from the broadside mill.

2. A hot strip mill comprising a scale breaker for rolling slabs endwise, a pusher for actuating said slabs sidewise, a roll stand having a pass-line at right angles to that of said scale breaker forreceiving said slabs for cross rolling, and a finishing mill having a pass-line at right angles to said broadside mill disposed to receive the slabs as they are discharged from the latter.

3. A hot strip mill comprising a source of highly heated metal slabs, a scale breakerfor rolling said slabs endwise, a roll having a pass-line stand at right angles to that of said scale breaker, a pusher in alignment with said roll stand for actuating said slabs sidewise thereto for cross rolling therein, and a finishing mill having a pass-line at right angles to said broadside mill disposed to receive the slabs as they are discharged from the latter.

4. A hot strip mill comprising a source of heated slabs, a scale breaker for removing the scales from said slabs, a roll stand broadside to said scale breaker for cross rolling said slabs, a pusher for changing the direction of said slabs between said scale breaker and said roll stand without changing their angular positions, and a plurality of roll stands in alignment parallel to said scale breaker for rolling said slabs lengthwise to reduce them to finished strip.

5. A hot strip mill comprising a source of heated slabs. a scale breaker for rolling said slabs lengthwise, a roll stand broadside to said scale breaker for cross rolling said slabs, a pusher for changing the direction of said slabs between said scale breaker and said roll stand without changing their angular positions, and means for chang-. ing the direction of said slabs after passing the first roll stand to supply them to the alignedroll stands without changing the angular positions of said slabs.

6. A hot strip mill comprising a furnace for heating slabsand from which heated slabs are pushed, a stationary stop at the foot of an incline from said furnace and adapted to be struck with force by said slabs to loosen scale on the latter, a scale breaker for said slabs, a stationary abutment against which the slabs are actuated after passing through the scale breaker, a roll stand for said slabs, a conveyor for receiving slabs from said roll stand, means associated with said conveyor for stopping said slabs to further loosen any scale remaining thereon, and roll stands for reducing the scale-free slabs to strip.

7. The method of hot rolling strip from slabs which comprises heating a slab, rolling the slab lengthwise to break the scale thereon, cross rolling the slab sidewise, without changing its angular position, to a width equal to that desired for the strip, and then without changing the angular position of the slab rolling it lengthwise to reduce it to strip.

8. The method of hot rolling strip which comprises heating a slab andthen successively and without change in its angular position rolling it lengthwise to break the scale thereon, rolling said slab sidewise to increase its width, and rolling said slab lengthwise to reduce its thickness and to finish said strip.

9. A hot strip mill comprising apparatus for treating slabs including a scale breaker, a roll stand for cross rolling said slabs, said scale breaker and said roll stand being at right angles to each other to permit a slab being moved therebetween by changing its direction without changing its angular position, and a finishing mill disposed at right angles to said cross-rolling stand arranged to receive the slabs as they are discharged from the latter.

10. A hot strip mill comprising a furnace and apparatus for treating slabs to prepare them for reduction rolling, including a broadside mill and a scale breaker arranged at right angles to each other to permit slabs to pass therebetween without rotation and with a single changeof direction, and a finishing mill disposed at right angles to said broadside mill and arranged to treat the slabs endwise after they leave the broadside mill.

11. A hot strip mill comprising a furnace for heating slabs, apparatus for treating said heated slabs to prepare them for reduction rolling, said apparatus comprising a broadside mill for cross-- rolling said slabs anda scale breaker for treating said slabs without rotation of said slabs in passing from said furnace through said apparatus. and aflnishing mill'disp'osed at right angles tosaidbroadsidemillandarranged totreatthe slabs endwise after they leave the broadside mill.

12. A hot strip mill comprising a furnace for heating slabs, apparatus for treating said heated slabs to prepare them for reduction rolling, said apparatus comprising a broadside mill for crossrolling'said slabs and a scale breaker for treating said slabs in the order stated without rotation of said slabs in passing through said apparatus, and a finishing mill disposed at rightangles to said broadside mill and arranged to treat said slabs lengthwise after they leave the broadside mill.

13. A hot strip mill comprising a. furnace for heating slabs, apparatus for treating said heated slabs to prepare them for reduction rolling, said apparatus comprising a scale breaker. and a broadside mill-for cross rolling said slabs in the order stated withoutrotation of said slabs in passing through said apparatus, and a finishing mill disposed at right angles to said broadside mill and arranged to treat the slabs endwise after they leave the broadside mill.

14. The method of hot rolling strip from slabs which comprises heating a slab, cram-rolling the slab sidewise, and then without changing its angular position treating it to remove the scale therefrom, rolling the slab lengthwise to reduce it to strip.

15. The method of hot rolling strip from slabs which comprises heating a slab, cross-rolling the slab sidewise, then without changing its angular podtion subjecting it to edgewise pressure to true the edges thereof and remove the scale therefrom, and then rolling the slab lengthwise to reduce it to I Patent No. 1,989,532.

.(Seal) cennncm: 0F comacnon.

January 29, 1935.

JOHN A. SMITMANS.

It is hereby certitied. thatnerrorm-appears intrheprinted specification of the above numbered patent requiring correction as follows: Page 2, second column, line'34, a claim 3, strike'ont the word stand'v' and insert the same after "roll" in same line; and that the said Letters Patent should he read with this correction. therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of March, A. D. 1935.-

Lcsl ie Frazer Acting Comissionerof Patents. 

